<template>
  <div class="container">
    <van-nav-bar
      fixed
      left-arrow
      @click-left="$router.back()"
      title="小智同学"
    ></van-nav-bar>

    <!-- 聊天记录区域 -->
    <div ref="chatList" class="chat-list">
      <div v-for="(item, index) in list" :key="index">
        <!-- 左侧是机器人小智 -->
        <div v-if="!item.isMe" class="chat-item left">
          <van-image
            fit="cover"
            round
            :src="require('@/assets/girl.jpg')"
          />
          <div class="chat-pao">{{ item.msg }}</div>
        </div>

        <!-- 右侧是当前用户 -->
        <div  v-else class="chat-item right">
          <div class="chat-pao my">{{ item.msg }}</div>
          <van-image fit="cover" round :src="$store.state.userInfo.photo" />
        </div>
      </div>
    </div>

    <!-- 输入区域 -->
    <div class="reply-container van-hairline--top">
      <van-field @keyup.enter="send" v-model="msg" placeholder="说点什么...">
        <span @click="send" slot="button" style="font-size:12px;color:#999">
          提交
        </span>
      </van-field>
    </div>
  </div>
</template>

<script>
import io from 'socket.io-client'
export default {
  name: 'UserChat',
  data () {
    return {
      msg: '',
      socket: null,
      list: []
    }
  },
  created () {
    // 获取用户资料
    this.$store.dispatch('reqUserInfo')
    // 建立链接
    this.socket = io('http://geek.itheima.net', {
      query: {
        token: this.$store.state.tokenObj.token
      },
      transports: ['websocket']
    })

    // 接收服务器的消息
    this.socket.on('message', e => {
      this.list.push({
        msg: e.msg,
        isMe: false
      })
      this.$nextTick(() => {
        // 让滚动条滚到最后
        this.$refs.chatList.scrollTop = this.$refs.chatList.scrollHeight
      })
    })
  },
  methods: {
    send () {
      // 非空判断
      if (this.msg === '') return this.$toast('请输入内容')
      // 把输入的内容发给服务器
      this.socket.emit('message', {
        msg: this.msg,
        timestamp: Date.now()
      })
      // 把输入内容加到数组里
      this.list.push({
        msg: this.msg,
        isMe: true
      })
      // 把输入内容清空
      this.msg = ''

      this.$nextTick(() => {
        // 让滚动条滚到最后
        this.$refs.chatList.scrollTop = this.$refs.chatList.scrollHeight
      })
    }
  }
}
</script>

<style lang="scss" scoped>
.container {
  height: 100%;
  width: 100%;
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  background: #fafafa;
  padding: 46px 0 50px 0;
  .chat-list {
    height: 100%;
    overflow-y: scroll;
    .chat-item {
      padding: 10px;
      .van-image {
        vertical-align: top;
        width: 40px;
        height: 40px;
      }
      .chat-pao {
        vertical-align: top;
        display: inline-block;
        max-width: 70%;
        min-height: 40px;
        line-height: 38px;
        border: 0.5px solid #c2d9ea;
        border-radius: 4px;
        position: relative;
        padding: 0 10px;
        background-color: #e0effb;
        word-break: break-all;
        font-size: 14px;
        color: #333;
        &::before {
          content: '';
          width: 10px;
          height: 10px;
          position: absolute;
          top: 12px;
          border-top: 0.5px solid #c2d9ea;
          border-right: 0.5px solid #c2d9ea;
          background: #e0effb;
        }
      }
      .chat-pao.my {
        background-color: #9eea6a;
        &::before {
          content: '';
          background: #9eea6a;
        }
      }
    }
  }
}
.chat-item.right {
  text-align: right;
  .chat-pao {
    margin-left: 0;
    margin-right: 15px;
    &::before {
      right: -6px;
      transform: rotate(45deg);
    }
  }
}
.chat-item.left {
  text-align: left;
  .chat-pao {
    margin-left: 15px;
    margin-right: 0;
    &::before {
      left: -5px;
      transform: rotate(-135deg);
    }
  }
}
.reply-container {
  position: fixed;
  left: 0;
  bottom: 0;
  height: 44px;
  width: 100%;
  background: #f5f5f5;
  z-index: 9999;
}
</style>
